I don't remember ever seeing it used in the 3.5 decades I've played.
Right.Well I don't think it was actually a thing until that last, most recent .5 of a decade. IIRC Dispel Magic has been around forever but Counterspell as a spell is new to 5E.
It wasn't just cumbersome in 3E; it was a horrible waste of the action economy. It was almost always preferable to just let them cast their spell, and then Dispel the effect (or cast the reversal spell) on your own turn, because trying to counter it during the cast required you to ready an action and successfully identify the spell being cast and have the exact same spell available to cast as the counter. If they ended up casting a spell that you didn't have available, then your turn was wasted. You also had the much, much more effective alternative of readying an action to attack someone if they tried to cast a spell, which had the benefit of working on any spell and also dealing damage.Right.
I don't think counterspelling existed until 3e, and there it's quite different and IMO more cumbersome (so used less).